Seroprevalence and molecular characterization of peste des petits ruminants virus in selected areas of Tanzania

Peste des petits ruminants (PPR) is a contagious disease of major economic importance affecting small ruminants mainly sheep, goats as well as wild small ungulates. This study was conducted to determine the prevalence of PPR Virus antibodies and establish the phylogenetic relation of PPRV isolates obtained from sheep and goats from 17 districts. Furthermore, vaccinated population of sheep and goats were sampled to assess the potency of PPR vaccine. A total of 1055 samples were collected, 969 were tested serologically using c-ELISA and 86 samples were analysed using Reverse Transcription Polymerase Chain Reaction (RT-PCR). Out of 969 sera samples from 17 districts screened using, c-ELISA came from southern districts of Tanzania and Pugu livestock auction market from which samples from six districts were found to have animals positive for PPRV antibodies. An overall seroprevalence of 31.16% (n= 77) sheep and 21.63 % (n= 892) goats was obtained. Variation among the most and least affected districts with PPRV from southern Tanzania was significant, the p value was <0.0001, 95 CI (49.425 – 87.330) (p=0.05). Out of 17 districts sampled, five districts had samples which were positive to RT-PCR. The phylogenetic analysis of these samples clusters the isolate obtained in this study to lineage II. In more than 90% of vaccinated sheep and goat in Masasi and Tunduru districts had no antibodies for PPR one year post vaccination. Normally the vaccine protects animal for three years. This calls for post vaccination sero- monitoring. This study confirms that PPRV had spread into five districts of Mtwara, Nanyumbu, Singida, Mpwapwa and Meatu not reported earlier. There is a need to carry out an extensive study to establish and map the actual spread of PPRV in Tanzania in order to design and implement comprehensive PPRV control strategies.